/// <summary>
        /// Processes requests made to the Graph Store HTTP Protocol endpoint and invokes the appropriate methods on the Protocol Processor that is in use
        /// </summary>
        /// <param name="context">HTTP Context</param>
        /// <remarks>
        /// <para>
        /// Implementations may override this if necessary - if the implementation is only providing additional logic such as authentication, ACLs etc. then it is recommended that the override applies its logic and then calls the base method since this base method will handle much of the error handling and sending of appropriate HTTP Response Codes.
        /// </para>
        /// </remarks>
        public virtual void ProcessRequest(HttpContext context)
        {
            this._config = this.LoadConfig(context, out this._basePath);
            WebContext webContext = new WebContext(context);

            // Add our Standard Headers
            HandlerHelper.AddStandardHeaders(webContext, this._config);

            if (context.Request.HttpMethod.Equals("OPTIONS"))
            {
                // OPTIONS requests always result in the Service Description document
                IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, new Uri(UriFactory.Create(context.Request.Url.AbsoluteUri), this._basePath));
                HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
                return;
            }

            // Check whether we need to use authentication
            if (!HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, context.Request.HttpMethod))
            {
                return;
            }

            try
            {
                // Invoke the appropriate method on our protocol processor
                switch (context.Request.HttpMethod)
                {
                case "GET":
                    this._config.Processor.ProcessGet(webContext);
                    break;

                case "PUT":
                    this._config.Processor.ProcessPut(webContext);
                    break;

                case "POST":
                    Uri serviceUri = new Uri(UriFactory.Create(context.Request.Url.AbsoluteUri), this._basePath);
                    if (context.Request.Url.AbsoluteUri.Equals(serviceUri.AbsoluteUri))
                    {
                        // If there is a ?graph parameter or ?default parameter then this is a normal Post
                        // Otherwise it is a PostCreate
                        if (context.Request.QueryString["graph"] != null)
                        {
                            this._config.Processor.ProcessPost(webContext);
                        }
                        else if (context.Request.QueryString.AllKeys.Contains("default") || Regex.IsMatch(context.Request.QueryString.ToString(), BaseProtocolProcessor.DefaultParameterPattern))
                        {
                            this._config.Processor.ProcessPost(webContext);
                        }
                        else
                        {
                            this._config.Processor.ProcessPostCreate(webContext);
                        }
                    }
                    else
                    {
                        this._config.Processor.ProcessPost(webContext);
                    }
                    break;

                case "DELETE":
                    this._config.Processor.ProcessDelete(webContext);
                    break;

                case "HEAD":
                    this._config.Processor.ProcessHead(webContext);
                    break;

                case "PATCH":
                    this._config.Processor.ProcessPatch(webContext);
                    break;

                default:
                    // For any other HTTP Verb we send a 405 Method Not Allowed
                    context.Response.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
                    break;
                }

                // Update the Cache as the request may have changed the endpoint
                this.UpdateConfig(context);
            }
            catch (SparqlHttpProtocolUriResolutionException)
            {
                // If URI Resolution fails we send a 400 Bad Request
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
            }
            catch (SparqlHttpProtocolUriInvalidException)
            {
                // If URI is invalid we send a 400 Bad Request
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
            }
            catch (NotSupportedException)
            {
                // If Not Supported we send a 405 Method Not Allowed
                context.Response.StatusCode = (int)HttpStatusCode.MethodNotAllowed;
            }
            catch (NotImplementedException)
            {
                // If Not Implemented we send a 501 Not Implemented
                context.Response.StatusCode = (int)HttpStatusCode.NotImplemented;
            }
            catch (RdfWriterSelectionException)
            {
                // If we can't select a valid Writer when returning content we send a 406 Not Acceptable
                context.Response.StatusCode = (int)HttpStatusCode.NotAcceptable;
            }
            catch (RdfParserSelectionException)
            {
                // If we can't select a valid Parser when receiving content we send a 415 Unsupported Media Type
                context.Response.StatusCode = (int)HttpStatusCode.UnsupportedMediaType;
            }
            catch (RdfParseException)
            {
                // If we can't parse the received content successfully we send a 400 Bad Request
                context.Response.StatusCode = (int)HttpStatusCode.BadRequest;
            }
            catch (Exception)
            {
                // For any other error we'll send a 500 Internal Server Error
                context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            }
        }
        /// <summary>
        /// Processes the request by loading the Configuration in order to obtain the Graph to be served and then serving it to the client
        /// </summary>
        /// <param name="context">HTTP Context</param>
        public void ProcessRequest(HttpContext context)
        {
            this._config = this.LoadConfig(context);
            WebContext webContext = new WebContext(context);

            // Add our Standard Headers
            HandlerHelper.AddStandardHeaders(webContext, this._config);

            // Check whether we need to use authentication
            // If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
            bool isAuth = true;

            if (this._config.UserGroups.Any())
            {
                // If we have user
                isAuth = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups);
            }
            if (!isAuth)
            {
                return;
            }

            // Check whether we can just send a 304 Not Modified
            if (HandlerHelper.CheckCachingHeaders(webContext, this._config.ETag, null))
            {
                context.Response.StatusCode = (int)HttpStatusCode.NotModified;
                HandlerHelper.AddCachingHeaders(webContext, this._config.ETag, null);
                return;
            }

            try
            {
                String[] acceptTypes = webContext.GetAcceptTypes();

                // Retrieve an appropriate MIME Type Definition which can be used to get a Writer
                MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(acceptTypes).FirstOrDefault(d => d.CanWriteRdf);
                if (definition == null)
                {
                    throw new RdfWriterSelectionException("No MIME Type Definitions have a registered RDF Writer for the MIME Types specified in the HTTP Accept Header");
                }
                IRdfWriter writer = this.SelectWriter(definition);
                HandlerHelper.ApplyWriterOptions(writer, this._config);

                IGraph g = this.ProcessGraph(this._config.Graph);
                if (this._config.ETag == null)
                {
                    this._config.ETag = this.ComputeETag(g);
                }

                // Serve the Graph to the User
                context.Response.ContentType = definition.CanonicalMimeType;
                HandlerHelper.AddCachingHeaders(webContext, this._config.ETag, null);
                if (writer is IHtmlWriter)
                {
                    if (!this._config.Stylesheet.Equals(String.Empty))
                    {
                        ((IHtmlWriter)writer).Stylesheet = this._config.Stylesheet;
                    }
                }
                context.Response.ContentEncoding = definition.Encoding;
                HandlerHelper.ApplyWriterOptions(writer, this._config);
                writer.Save(g, new StreamWriter(context.Response.OutputStream, definition.Encoding));

                this.UpdateConfig(context);
            }
            catch (RdfWriterSelectionException)
            {
                context.Response.StatusCode = (int)HttpStatusCode.NotAcceptable;
            }
            catch
            {
                context.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            }
        }
        /// <summary>
        /// Processes SPARQL Update requests
        /// </summary>
        /// <param name="context">HTTP Context</param>
        public void ProcessRequest(HttpContext context)
        {
            this._config = this.LoadConfig(context);
            WebContext webContext = new WebContext(context);

            // Add our Standard Headers
            HandlerHelper.AddStandardHeaders(webContext, this._config);

            // Options we need to determine based on the HTTP Method used
            String[]      updates;
            String        updateText        = null;
            List <String> userDefaultGraphs = new List <String>();
            List <String> userNamedGraphs   = new List <String>();

            try
            {
                // Decide what to do based on the HTTP Method
                switch (context.Request.HttpMethod.ToUpper())
                {
                case "OPTIONS":
                    // OPTIONS requests always result in the Service Description document
                    IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
                    HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
                    return;

                case "HEAD":
                    // Just return from a HEAD request
                    return;

                case "GET":
                    // A GET with an update parameter is a Bad Request
                    updates = context.Request.QueryString.GetValues("update");
                    if (updates != null && updates.Length > 0)
                    {
                        throw new ArgumentException("Updates cannot be submitted as GET requests");
                    }

                    // Otherwise GET either results in the Service Description if appropriately conneg'd or
                    // the update form if enabled

                    try
                    {
                        // If we might show the Update Form only show the Description if the selected writer is
                        // not a HTML writer
                        MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(webContext.GetAcceptTypes()).FirstOrDefault(d => d.CanWriteRdf);
                        if (definition != null)
                        {
                            IRdfWriter writer = definition.GetRdfWriter();
                            if (!(writer is IHtmlWriter))
                            {
                                // If not a HTML Writer selected then show the Service Description Graph
                                // unless an error occurs creating it
                                IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
                                context.Response.ContentType     = definition.CanonicalMimeType;
                                context.Response.ContentEncoding = definition.Encoding;
                                writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
                                return;
                            }
                        }
                    }
                    catch
                    {
                        // Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
                    }

                    // If a Writer can't be selected then we'll either show the Update Form or return a 400 Bad Request
                    if (this._config.ShowUpdateForm)
                    {
                        this.ShowUpdateForm(context);
                    }
                    else
                    {
                        throw new ArgumentException("Updates cannot be submitted as GET requests");
                    }
                    return;

                case "POST":

                    if (context.Request.ContentType != null)
                    {
                        MimeTypeSelector contentType = MimeTypeSelector.Create(context.Request.ContentType, 0);
                        if (contentType.Type.Equals(MimeTypesHelper.WWWFormURLEncoded))
                        {
                            // Form URL Encoded was declared type so expect an update parameter in the Form parameters
                            updates = context.Request.Form.GetValues("update");
                            if (updates == null)
                            {
                                throw new ArgumentException("Required update parameter in POST body was missing");
                            }
                            if (updates.Length == 0)
                            {
                                throw new ArgumentException("Required update parameter in POST body was missing");
                            }
                            if (updates.Length > 1)
                            {
                                throw new ArgumentException("The update parameter was specified multiple times in the POST body");
                            }
                            updateText = updates[0];

                            // For Form URL Encoded the Using/Using Named Graphs may be specified by Form parameters
                            // Get the USING URIs (if any)
                            if (context.Request.Form["using-graph-uri"] != null)
                            {
                                userDefaultGraphs.AddRange(context.Request.Form.GetValues("using-graph-uri"));
                            }
                            // Get the USING NAMED URIs (if any)
                            if (context.Request.Form["using-named-graph-uri"] != null)
                            {
                                userNamedGraphs.AddRange(context.Request.Form.GetValues("using-named-graph-uri"));
                            }

                            break;
                        }
                        else if (contentType.Type.Equals(MimeTypesHelper.SparqlUpdate))
                        {
                            // application/sparql-update was declared type so expect utf-8 charset (if present)
                            if (contentType.Charset != null && !contentType.Charset.ToLower().Equals(MimeTypesHelper.CharsetUtf8))
                            {
                                throw new ArgumentException("HTTP POST request was received with a " + MimeTypesHelper.SparqlUpdate + " Content-Type but a non UTF-8 charset parameter");
                            }

                            using (StreamReader reader = new StreamReader(context.Request.InputStream))
                            {
                                updateText = reader.ReadToEnd();
                                reader.Close();
                            }

                            // For application/sparql-update the Using/Using Named Graphs may be specified by querystring parameters
                            // Get the USING URIs (if any)
                            if (context.Request.QueryString["using-graph-uri"] != null)
                            {
                                userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("using-graph-uri"));
                            }
                            // Get the USING NAMED URIs (if any)
                            if (context.Request.QueryString["using-named-graph-uri"] != null)
                            {
                                userNamedGraphs.AddRange(context.Request.QueryString.GetValues("using-named-graph-uri"));
                            }

                            break;
                        }
                        else
                        {
                            throw new ArgumentException("HTTP POST made to SPARQL update endpoint had an invalid Content-Type header, only " + MimeTypesHelper.WWWFormURLEncoded + " and " + MimeTypesHelper.SparqlUpdate + " are acceptable");
                        }
                    }
                    throw new ArgumentException("HTTP POST made to SPARQL Query endpoint was missing the required Content-Type header");

                default:
                    throw new NotSupportedException("HTTP " + context.Request.HttpMethod.ToUpper() + " is not supported by a SPARQL Update endpoint");
                }

                // Clean up protocol provided dataset
                userDefaultGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
                userNamedGraphs.RemoveAll(g => String.IsNullOrEmpty(g));

                // Now we're going to parse the Updates
                SparqlUpdateParser parser = new SparqlUpdateParser();
                parser.DefaultBaseUri      = context.Request.Url;
                parser.ExpressionFactories = this._config.ExpressionFactories;
                SparqlUpdateCommandSet commands = parser.ParseFromString(updateText);

                // Check whether we need to use authentication
                // If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
                bool isAuth = true, requireActionAuth = false;
                if (this._config.UserGroups.Any())
                {
                    // If we have user
                    isAuth            = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups);
                    requireActionAuth = true;
                }
                if (!isAuth)
                {
                    return;
                }

                // First check actions to see whether they are all permissible and apply USING/USING NAMED parameters
                foreach (SparqlUpdateCommand cmd in commands.Commands)
                {
                    // Authenticate each action
                    bool actionAuth = true;
                    if (requireActionAuth)
                    {
                        actionAuth = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, this.GetPermissionAction(cmd));
                    }
                    if (!actionAuth)
                    {
                        throw new SparqlUpdatePermissionException("You are not authorised to perform the " + this.GetPermissionAction(cmd) + " action");
                    }

                    // Check whether we need to (and are permitted to) apply USING/USING NAMED parameters
                    if (userDefaultGraphs.Count > 0 || userNamedGraphs.Count > 0)
                    {
                        BaseModificationCommand modify = cmd as BaseModificationCommand;
                        if (modify != null)
                        {
                            if (modify.GraphUri != null || modify.UsingUris.Any() || modify.UsingNamedUris.Any())
                            {
                                // Invalid if a command already has a WITH/USING/USING NAMED
                                throw new SparqlUpdateMalformedException("A command in your update request contains a WITH/USING/USING NAMED clause but you have also specified one/both of the using-graph-uri or using-named-graph-uri parameters which is not permitted by the SPARQL Protocol");
                            }
                            else
                            {
                                // Otherwise go ahead and apply
                                userDefaultGraphs.ForEach(u => modify.AddUsingUri(UriFactory.Create(u)));
                                userNamedGraphs.ForEach(u => modify.AddUsingNamedUri(UriFactory.Create(u)));
                            }
                        }
                    }
                }

                // Then assuming we got here this means all our actions are permitted so now we can process the updates
                this.ProcessUpdates(commands);

                // Flush outstanding changes
                this._config.Processor.Flush();

                // Update the Cache as the request may have changed the endpoint
                this.UpdateConfig(context);
            }
            catch (RdfParseException parseEx)
            {
                HandleErrors(context, "Parsing Error", updateText, parseEx, (int)HttpStatusCode.BadRequest);
            }
            catch (SparqlUpdatePermissionException permEx)
            {
                HandleErrors(context, "Permissions Error", updateText, permEx, (int)HttpStatusCode.Forbidden);
            }
            catch (SparqlUpdateMalformedException malEx)
            {
                HandleErrors(context, "Malformed Update Error", updateText, malEx, (int)HttpStatusCode.BadRequest);
            }
            catch (SparqlUpdateException updateEx)
            {
                HandleErrors(context, "Update Error", updateText, updateEx);
            }
            catch (RdfException rdfEx)
            {
                HandleErrors(context, "RDF Error", updateText, rdfEx);
            }
            catch (NotSupportedException notSupEx)
            {
                HandleErrors(context, "HTTP Request Error", null, notSupEx, (int)HttpStatusCode.MethodNotAllowed);
            }
            catch (ArgumentException argEx)
            {
                HandleErrors(context, "HTTP Request Error", null, argEx, (int)HttpStatusCode.BadRequest);
            }
            catch (Exception ex)
            {
                HandleErrors(context, "Error", updateText, ex);
            }
        }
示例#4
0
        /// <summary>
        /// Processes a SPARQL Query Request
        /// </summary>
        /// <param name="context">HTTP Context</param>
        public void ProcessRequest(HttpContext context)
        {
            this._config = this.LoadConfig(context);
            WebContext webContext = new WebContext(context);

            //Add our Standard Headers
            HandlerHelper.AddStandardHeaders(webContext, this._config);

            //Options we need to determine based on the HTTP Method used
            String[]      queries;
            String        queryText         = null;
            List <String> userDefaultGraphs = new List <String>();
            List <String> userNamedGraphs   = new List <String>();

            try
            {
                //Decide what to do based on the HTTP Method
                switch (context.Request.HttpMethod.ToUpper())
                {
                case "OPTIONS":
                    //OPTIONS requests always result in the Service Description document
                    IGraph svcDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
                    HandlerHelper.SendToClient(webContext, svcDescrip, this._config);
                    return;

                case "HEAD":
                    //Just return from a HEAD request
                    return;

                case "GET":
                    //GET expects a query parameter in the querystring
                    queries = context.Request.QueryString.GetValues("query");
                    if (queries != null)
                    {
                        if (queries.Length > 1)
                        {
                            throw new ArgumentException("The query parameter was specified multiple times in the querystring");
                        }
                        queryText = queries.Length == 1 ? queries[0] : null;
                    }

                    //If no Query sent either show Query Form or give a HTTP 400 response
                    if (String.IsNullOrEmpty(queryText))
                    {
                        //If there is no Query we may return the SPARQL Service Description where appropriate
                        try
                        {
                            //If we might show the Query Form only show the Description if the selected writer is
                            //not a HTML writer
                            MimeTypeDefinition definition = MimeTypesHelper.GetDefinitions(HandlerHelper.GetAcceptTypes(webContext)).FirstOrDefault(d => d.CanWriteRdf);
                            if (definition != null)
                            {
                                IRdfWriter writer = definition.GetRdfWriter();
                                if (!this._config.ShowQueryForm || !(writer is IHtmlWriter))
                                {
                                    //If not a HTML Writer selected OR not showing Query Form then show the Service Description Graph
                                    //unless an error occurs creating it
                                    IGraph serviceDescrip = SparqlServiceDescriber.GetServiceDescription(this._config, UriFactory.Create(context.Request.Url.AbsoluteUri));
                                    context.Response.ContentType     = definition.CanonicalMimeType;
                                    context.Response.ContentEncoding = definition.Encoding;
                                    writer.Save(serviceDescrip, new StreamWriter(context.Response.OutputStream, definition.Encoding));
                                    return;
                                }
                            }
                        }
                        catch
                        {
                            //Ignore Exceptions - we'll just show the Query Form or return a 400 Bad Request instead
                        }

                        //Otherwise we'll either show the Query Form or return a 400 Bad Request
                        if (this._config.ShowQueryForm)
                        {
                            this.ShowQueryForm(context);
                        }
                        else
                        {
                            throw new ArgumentException("Missing required query parameter");
                        }
                        return;
                    }

                    //Get the Default Graph URIs (if any)
                    if (context.Request.QueryString["default-graph-uri"] != null)
                    {
                        userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("default-graph-uri"));
                    }
                    //Get the Named Graph URIs (if any)
                    if (context.Request.QueryString["named-graph-uri"] != null)
                    {
                        userNamedGraphs.AddRange(context.Request.QueryString.GetValues("named-graph-uri"));
                    }
                    break;

                case "POST":
                    //POST requires a valid content type
                    if (context.Request.ContentType != null)
                    {
                        MimeTypeSelector contentType = MimeTypeSelector.Create(context.Request.ContentType, 0);
                        if (contentType.Type.Equals(MimeTypesHelper.WWWFormURLEncoded))
                        {
                            //Form URL Encoded was declared type so expect a query parameter in the Form parameters
                            queries = context.Request.Form.GetValues("query");
                            if (queries == null)
                            {
                                throw new ArgumentException("Required query parameter in POST body was missing");
                            }
                            if (queries.Length == 0)
                            {
                                throw new ArgumentException("Required query parameter in POST body was missing");
                            }
                            if (queries.Length > 1)
                            {
                                throw new ArgumentException("The query parameter was specified multiple times in the POST body");
                            }
                            queryText = queries[0];

                            //For Form URL Encoded the Default/Named Graphs may be specified by Form parameters
                            //Get the Default Graph URIs (if any)
                            if (context.Request.Form["default-graph-uri"] != null)
                            {
                                userDefaultGraphs.AddRange(context.Request.Form.GetValues("default-graph-uri"));
                            }
                            //Get the Named Graph URIs (if any)
                            if (context.Request.Form["named-graph-uri"] != null)
                            {
                                userNamedGraphs.AddRange(context.Request.Form.GetValues("named-graph-uri"));
                            }

                            break;
                        }
                        else if (contentType.Type.Equals(MimeTypesHelper.SparqlQuery))
                        {
                            //application/sparql-query was declared type so expect utf-8 charset (if present)
                            if (contentType.Charset != null && !contentType.Charset.ToLower().Equals(MimeTypesHelper.CharsetUtf8))
                            {
                                throw new ArgumentException("HTTP POST request was received with a " + MimeTypesHelper.SparqlQuery + " Content-Type but a non UTF-8 charset parameter");
                            }

                            //Read the query from the request body
                            using (StreamReader reader = new StreamReader(context.Request.InputStream))
                            {
                                queryText = reader.ReadToEnd();
                                reader.Close();
                            }

                            //For application/sparql-query the Default/Named Graphs may be specified by querystring parameters
                            //Get the Default Graph URIs (if any)
                            if (context.Request.QueryString["default-graph-uri"] != null)
                            {
                                userDefaultGraphs.AddRange(context.Request.QueryString.GetValues("default-graph-uri"));
                            }
                            //Get the Named Graph URIs (if any)
                            if (context.Request.QueryString["named-graph-uri"] != null)
                            {
                                userNamedGraphs.AddRange(context.Request.QueryString.GetValues("named-graph-uri"));
                            }

                            break;
                        }
                        else
                        {
                            throw new ArgumentException("HTTP POST made to SPARQL query endpoint had an invalid Content-Type header, only " + MimeTypesHelper.WWWFormURLEncoded + " and " + MimeTypesHelper.SparqlQuery + " are acceptable");
                        }
                    }
                    throw new ArgumentException("HTTP POST made to SPARQL Query endpoint was missing the required Content-Type header");

                default:
                    throw new NotSupportedException("HTTP " + context.Request.HttpMethod.ToUpper() + " is not supported by a SPARQL Query endpoint");
                }

                //Get non-standard options associated with the query
                long timeout        = 0;
                bool partialResults = this._config.DefaultPartialResults;

                //Get Timeout setting (if any)
                if (context.Request.QueryString["timeout"] != null)
                {
                    if (!Int64.TryParse(context.Request.QueryString["timeout"], out timeout))
                    {
                        timeout = this._config.DefaultTimeout;
                    }
                }
                else if (context.Request.Form["timeout"] != null)
                {
                    if (!Int64.TryParse(context.Request.Form["timeout"], out timeout))
                    {
                        timeout = this._config.DefaultTimeout;
                    }
                }
                //Get Partial Results Setting (if any);
                if (context.Request.QueryString["partialResults"] != null)
                {
                    if (!Boolean.TryParse(context.Request.QueryString["partialResults"], out partialResults))
                    {
                        partialResults = this._config.DefaultPartialResults;
                    }
                }
                else if (context.Request.Form["partialResults"] != null)
                {
                    if (!Boolean.TryParse(context.Request.Form["partialResults"], out partialResults))
                    {
                        partialResults = this._config.DefaultPartialResults;
                    }
                }

                //Now we're going to parse the Query
                SparqlQueryParser parser = new SparqlQueryParser(this._config.Syntax);
                parser.DefaultBaseUri      = context.Request.Url;
                parser.ExpressionFactories = this._config.ExpressionFactories;
                parser.QueryOptimiser      = this._config.QueryOptimiser;
                SparqlQuery query = parser.ParseFromString(queryText);
                query.AlgebraOptimisers         = this._config.AlgebraOptimisers;
                query.PropertyFunctionFactories = this._config.PropertyFunctionFactories;

                //Check whether we need to use authentication
                //If there are no user groups then no authentication is in use so we default to authenticated with no per-action authentication needed
                bool isAuth = true, requireActionAuth = false;
                if (this._config.UserGroups.Any())
                {
                    //If we have user
                    isAuth            = HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups);
                    requireActionAuth = true;
                }
                if (!isAuth)
                {
                    return;
                }

                //Is this user allowed to make this kind of query?
                if (requireActionAuth)
                {
                    HandlerHelper.IsAuthenticated(webContext, this._config.UserGroups, this.GetPermissionAction(query));
                }

                //Clear query dataset if there is a protocol defined one
                userDefaultGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
                userNamedGraphs.RemoveAll(g => String.IsNullOrEmpty(g));
                bool isProtocolDataset = false;
                if (userDefaultGraphs.Count > 0 || userNamedGraphs.Count > 0)
                {
                    query.ClearDefaultGraphs();
                    query.ClearNamedGraphs();
                    isProtocolDataset = true;
                }

                //Set the Default Graph URIs (if any)
                if (isProtocolDataset)
                {
                    foreach (String userDefaultGraph in userDefaultGraphs)
                    {
                        query.AddDefaultGraph(UriFactory.Create(userDefaultGraph));
                    }
                }
                else if (!this._config.DefaultGraphURI.Equals(String.Empty))
                {
                    //Only applies if the Query doesn't specify any Default Graph and there wasn't a protocol defined
                    //dataset present
                    if (!query.DefaultGraphs.Any())
                    {
                        query.AddDefaultGraph(UriFactory.Create(this._config.DefaultGraphURI));
                    }
                }

                //Set the Named Graph URIs (if any)
                if (isProtocolDataset)
                {
                    query.ClearNamedGraphs();
                    foreach (String userNamedGraph in userNamedGraphs)
                    {
                        query.AddNamedGraph(UriFactory.Create(userNamedGraph));
                    }
                }

                //Set Timeout setting
                if (timeout > 0)
                {
                    query.Timeout = timeout;
                }
                else
                {
                    query.Timeout = this._config.DefaultTimeout;
                }

                //Set Partial Results Setting
                query.PartialResultsOnTimeout = partialResults;

                //Set Describe Algorithm
                query.Describer = this._config.DescribeAlgorithm;

                //Now we can finally make the query and return the results
                Object result = this.ProcessQuery(query);
                this.ProcessResults(context, result);

                //Update the Cache as the request may have changed the endpoint
                this.UpdateConfig(context);
            }
            catch (RdfParseException parseEx)
            {
                HandleErrors(context, "Parsing Error", queryText, parseEx, (int)HttpStatusCode.BadRequest);
            }
            catch (RdfQueryTimeoutException timeoutEx)
            {
                HandleErrors(context, "Query Timeout Error", queryText, timeoutEx);
            }
            catch (RdfQueryException queryEx)
            {
                HandleErrors(context, "Update Error", queryText, queryEx);
            }
            catch (RdfWriterSelectionException writerSelEx)
            {
                HandleErrors(context, "Output Selection Error", queryText, writerSelEx, (int)HttpStatusCode.NotAcceptable);
            }
            catch (RdfException rdfEx)
            {
                HandleErrors(context, "RDF Error", queryText, rdfEx);
            }
            catch (NotSupportedException notSupEx)
            {
                HandleErrors(context, "HTTP Request Error", null, notSupEx, (int)HttpStatusCode.MethodNotAllowed);
            }
            catch (ArgumentException argEx)
            {
                HandleErrors(context, "HTTP Request Error", null, argEx, (int)HttpStatusCode.BadRequest);
            }
            catch (Exception ex)
            {
                HandleErrors(context, "Error", queryText, ex);
            }
        }